JP2005221933A - Electrostatic charge image developing toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic charge image developing toner which can be used in a low temperature fixing process and ensures contradictory functions such as hot storage resistance, mechanical strength and environmental stability of a charged state. <P>SOLUTION: The electrostatic charge image developing toner includes toner particles having shell layers on the surfaces of core particles comprising at least a first binder resin having a softening point of <100°C, a second binder resin having a softening point of ≥100°C and a colorant. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a toner for developing an electrostatic image.

  In recent years, in the field of electrostatic image developing toner, development of an electrophotographic apparatus suitable for the demand for higher image quality from the market, and toner usable for this, have been proceeding at a rapid pace. For example, a toner compatible with high image quality is required to have a sharp particle size distribution. When the particle diameters of the toners are uniform and the particle diameter distribution is sharpened, the development behavior of each individual toner particle is uniformed, so that the fine dot reproducibility is remarkably improved. However, it is not easy to sharpen the toner particle size distribution. On the other hand, an emulsion polymerization aggregation method has been proposed as a production method capable of arbitrarily controlling the shape and particle size distribution of toner particles. In this method, a polymer primary particle dispersion is prepared in advance by emulsion polymerization, and a colorant fine particle dispersion or a wax dispersion or the like is separately prepared, and the inorganic metal salt is mixed and stirred. After aggregating by adding a suitable aggregating agent such as the above, the polymer resin is fused by heating to obtain toner particles.

  On the other hand, there is an increasing demand for energy saving for the electrophotographic apparatus, but since a large amount of energy is required in the toner fixing process, a low-temperature fixing function for the toner is strongly demanded. Furthermore, from the trend of speeding up copying machines and saving space, a toner having further excellent low-temperature fixability is desired.

The heat melting characteristics related to the fixing function of the toner greatly depend on the thermophysical properties of the binder resin to be used. In order to lower the fixing temperature, it is necessary to lower the melting point and melt viscosity of the resin. However, when the melting point and melt viscosity of the binder resin are lowered, new problems such as reduction in heat-resistant storage stability and mechanical strength (stress resistance) of the toner and reduction in charging environment stability arise.
As described above, it is the actual situation that a toner that can simultaneously solve the problems such as low-temperature fixing property, heat-resistant storage property, mechanical strength, and charging environment stability has not been obtained yet.

  An object of the present invention is to provide a toner for developing an electrostatic charge image that can be used in a low-temperature fixing process, and further ensures contradictory functions such as heat-resistant storage stability, mechanical strength, and charging environment stability.

  The present invention contains toner particles having a shell layer on the surface of core particles comprising at least a first binder resin having a softening point of less than 100 ° C., a second binder resin having a softening point of 100 ° C. or more, and a colorant. The present invention relates to a toner for developing an electrostatic charge image.

  According to the present invention, excellent low-temperature fixability can be realized while ensuring good heat-resistant storage stability, mechanical strength, and charging environment stability of the toner.

  The electrostatic image developing toner of the present invention contains core-shell structure type toner particles having a shell layer on the surface of the core particles.

(Core particles)
The core particle is composed of at least a specific first binder resin, a second binder resin, and a colorant. The first binder resin constituting the core particle has a softening point (Tm) of less than 100 ° C, particularly 60 to 95 ° C, preferably 75 to 90 ° C, and the second binder resin is 100 ° C or more, particularly Those having a Tm of 100 to 150 ° C, preferably 105 to 135 ° C. In the present invention, since the core particle contains the first binder resin and the second binder resin having the above softening point, fixing at a relatively low temperature (for example, 95 ° C. or more and less than 106 ° C.) with respect to the conventional fixing process. However, the mechanical strength can be effectively secured. When the first binder resin is not used or the softening point of the first binder resin is 100 ° C. or higher, the fixed image is easily peeled off at the time of fixing at a relatively low temperature, and the low-temperature fixability is deteriorated. . If the second binder resin is not used, or if the softening point of the second binder resin is less than 100 ° C., a high temperature offset is easily generated during fixing, and the mechanical strength of the toner is reduced. Particle fragments adhere to the surface of the photoreceptor and cause image noise.

Preferred first and second binder resins further have the following physical properties:
First binder resin;
Glass transition temperature (Tg); 20-43 ° C, preferably 25-40 ° C
Second binder resin;
Tg: 45-80 ° C, preferably 50-70 ° C.

  The type of the first binder resin and the second binder resin is not particularly limited as long as it is a resin type conventionally used as a binder resin in the field of electrostatic image developing toner. For example, the first binder resin and the second binder resin are each independently made of one or more kinds of resins selected from the group consisting of vinyl resins, polyurethane resins, epoxy resins, and polyester resins. When the first binder resin or the second binder resin is composed of a plurality of different types of resins, the physical property values such as the softening point are different for each resin constituting the first binder resin or the second binder resin. It may be within the above range.

Preferred combinations of the first binder resin and the second binder resin include the combinations shown below:
(First binder resin, second binder resin) = (vinyl resin, vinyl resin) and (polyester resin, vinyl resin)

  The present invention does not prevent the core particles from containing a resin other than the first binder resin and the second binder resin as long as the object of the present invention is achieved.

  The core particle may have any configuration as long as it contains at least the first binder resin, the second binder resin, and the colorant. For example, at least the first binder resin fine particles, the second binder resin fine particles, and the colored particles May have a configuration in which agent fine particles are agglomerated / fused, or a configuration in which at least colorant fine particles are contained in one resin particle composed of a first binder resin and a second binder resin. You may have.

In this specification, “aggregation” is used based on the concept that at least a plurality of resin fine particles are simply attached. By “aggregation”, so-called hetero-aggregated particles (groups) are formed in which the constituent particles are in contact with each other, but the bonding due to melting of resin fine particles or the like is not formed. A group of particles formed by such “aggregation” is referred to as “aggregated particles”.
“Fusion” is a concept that is intended to form a bond as a unit of use and handling by forming a bond due to melting of resin fine particles, etc., at least at a part of the interface of each constituent particle in the aggregated particles. And The particle group that has undergone such “fusion” is referred to as “fused particles”.
“Aggregation / fusion” refers to an action in which aggregation and fusion occur simultaneously or stepwise, or an action that causes aggregation and fusion to occur simultaneously or stepwise.

  The core particle having a configuration in which at least the first binder resin fine particles, the second binder resin fine particles, and the colorant fine particles are aggregated / fused is first a resin fine particle dispersion of the first binder resin and the second binder resin. Then, the first binder resin fine particle dispersion and the second binder resin fine particle dispersion obtained are mixed with at least the colorant fine particle dispersion, and the fine particles are aggregated / fused. It is.

  The method for preparing the resin fine particle dispersion of the first binder resin and the second binder resin is not particularly limited as long as resin fine particles having a volume average particle diameter of 20 to 250 nm, preferably about 40 to 200 nm can be formed. Further, wet methods such as an emulsion polymerization method, a suspension polymerization method, and an emulsion dispersion method can be employed.

  For example, when preparing a fine particle dispersion of a radical polymerization resin such as a vinyl resin, an emulsion polymerization method is usually employed. Specifically, a polymerization composition containing a polymerizable monomer is dispersed in an aqueous medium containing a polymerization initiator, and emulsion polymerization is performed to such an extent that a physical property value such as a predetermined softening point is achieved. At this time, other toner components such as wax, charge control agent, and magnetic powder may be dispersed in an aqueous medium in advance to perform seed emulsion polymerization, or the other toner components may be dissolved in the polymerization composition in advance. It may be dispersed and emulsion polymerization may be performed. As a result, other toner components are contained in the resin fine particles.

  As the polymerizable monomer, it is preferable to use at least one monomer selected from radical polymerizable monomers having an acidic group, especially a radical polymerizable monomer as an essential constituent component. Moreover, a crosslinking agent can also be used as needed. Examples of such radical polymerizable monomers include aromatic vinyl monomers and (meth) acrylic acid ester monomers.

  Examples of the aromatic vinyl monomer include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, p-ethylstyrene, p- n-butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, 2,4 -Styrenic monomers such as dimethylstyrene and 3,4-dichlorostyrene and derivatives thereof.

  Examples of (meth) acrylic acid ester monomers include methyl acrylate, ethyl acrylate, butyl acrylate, -2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, methacrylic acid. Examples include butyl acid, hexyl methacrylate, 2-ethylhexyl methacrylate, ethyl β-hydroxyacrylate, propyl γ-aminoacrylate, stearyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and the like.

  Examples of radical polymerizable monomers having an acidic group include carboxylic acid groups such as acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, cinnamic acid, maleic acid monobutyl ester, maleic acid monooctyl ester, etc. Monomers; sulfonic acid group-containing monomers such as styrene sulfonic acid, allyl sulfosuccinic acid, and octyl allyl sulfosuccinic acid. All or part of the radical polymerizable monomer having an acidic group may have a structure of an alkali metal salt such as sodium or potassium or an alkaline earth metal salt such as calcium. The proportion of the radical polymerizable monomer having an acidic group in the polymerizable monomer (monomer mixture) used is preferably 0.1 to 20% by mass, more preferably 0.1 to 15% by mass. is there.

  A chain transfer agent can be added to the polymerization composition in order to control the degree of polymerization of the resin and adjust physical properties such as the softening point and molecular weight. As the chain transfer agent, a chain transfer agent generally used in radical polymerization reaction can be used, and is not particularly limited. Specific examples include mercaptans such as octyl mercaptan, dodecyl mercaptan, tert-dodecyl mercaptan, and styrene dimer.

  The radical polymerization initiator can be appropriately used as long as it is water-soluble. For example, persulfates such as potassium persulfate and ammonium persulfate, azo compounds such as 4,4′-azobis 4-cyanovaleric acid and its salts, 2,2′-azobis (2-amidinopropane) salts, peroxide compounds, etc. Is mentioned. The radical polymerization initiator may be used as a redox initiator combined with a reducing agent as necessary. By using a redox initiator, the polymerization activity is increased, the polymerization temperature can be lowered, and the polymerization time can be further shortened.

  A surfactant may be added to the aqueous medium. The surfactant is not particularly limited, but the following ionic and nonionic surfactants are preferably used.

  Examples of ionic surfactants include sulfonates (sodium dodecylbenzenesulfonate, sodium arylalkylpolyethersulfonate, 3,3-disulfonediphenylurea-4,4-diazo-bis-amino-8-naphthol-6- Sodium sulfonate, ortho-carboxybenzene-azo-dimethylaniline, 2,2,5,5-tetramethyl-triphenylmethane-4,4-diazo-bis-6-naphthol-6-sulfonate sodium, etc.), sulfuric acid Ester salt (sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, etc.), fatty acid salt (sodium oleate, sodium laurate, sodium caprate, sodium caprylate, sodium caproate, potassium stearate, olein) Calcium, etc.) and the like.

  Nonionic surfactants include polyethylene oxide, polypropylene oxide, combinations of polypropylene oxide and polyethylene oxide, esters of polyethylene glycol and higher fatty acids, alkylphenol polyethylene oxide, esters of higher fatty acids and polyethylene glycol, esters of higher fatty acids and polypropylene oxide. Sorbitan ester and the like can be mentioned, but they may be used in combination with the ionic surfactant described above as necessary.

  In the present invention, the nonionic surfactant is used not only as an emulsifier during emulsion polymerization, but also for the purpose of stabilizing the dispersion of each fine particle and adjusting the cohesive force of the dispersed fine particles in the agglomeration step described below. In other words, since the nonionic surfactant has a markedly reduced dispersion stabilizing power at the cloud point or higher, an appropriate amount can be allowed to coexist with the ionic surfactant during the preparation of the fine particle dispersion. By adding an appropriate amount in advance, it becomes possible to adjust the cohesive force between particles based on the control of the coagulation temperature, and it is possible to realize the uniformity and efficiency of cohesion of particles.

  For example, when preparing a fine particle dispersion of a condensation polymerization resin such as a polyester-based resin, an emulsion dispersion method is usually employed. Specifically, a resin having a physical property value such as a predetermined softening point, for example, a resin solution obtained by dissolving a polyester resin in a water-insoluble organic solvent is dispersed in an aqueous medium to form an O / W emulsion, and heated. To remove the water-insoluble organic solvent. At this time, other toner components such as wax, charge control agent and magnetic powder may be preliminarily dissolved and dispersed in the resin solution to be contained in the resin fine particles.

  The resin applied to the emulsification dispersion method is not particularly limited as long as it is soluble in a water-insoluble organic solvent, but the case where a polyester resin is used will be described below.

  The polyester resin is not particularly limited as long as it has a physical property value such as the predetermined softening point, and among them, those containing etherified diphenols as alcohol components and aromatic dicarboxylic acids as acid components are particularly preferable. preferable.

  Examples of etherified diphenols include polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3,3) -2,2-bis (4-hydroxy). Phenyl) propane, polyoxypropylene (2,0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene ( 2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2,2) -2,2-bis (4-hydroxyphenyl) propane and the like.

  As an alcohol component, together with etherified diphenols, for example, diols such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, Sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene and the like may be used.

  Examples of aromatic dicarboxylic acids that can be used include aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid, acid anhydrides thereof, or lower alkyl esters thereof.

  As the acid component, fumaric acid, maleic acid, succinic acid, aliphatic dicarboxylic acid such as alkyl or alkenyl succinic acid having 4 to 18 carbon atoms, aliphatic dicarboxylic acid such as acid anhydride or lower alkyl ester thereof is used. Also good.

  As acid components, 1,2,4-benzenetricarboxylic acid (trimellitic acid), 1,2,5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanenetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid, tetra ( Methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, their anhydrides, lower alkyl esters and other polycarboxylic acids such as adjusting the acid value of the polyester resin and improving the resin strength A small amount may be used for the purpose as long as the translucency is not impaired.

  A urethane-modified polyester resin obtained by reacting a polyester resin with isocyanate, an acrylic-modified polyester resin, or the like can also be used as the polyester resin.

  Water-insoluble organic solvents are used to dissolve or disperse toner components (resin and other toner components such as wax, charge control agent and magnetic powder as required) such as toluene, benzene, xylene, methylene chloride. , Chloroform, carbon tetrachloride, dimethyl ether, diethyl ether, methyl acetate, ethyl acetate, butyl acetate, methyl propionate, ethyl propionate, butyl propionate, dimethyl oxalate, diethyl oxalate, dimethyl succinate, diethyl succinate, diethylene glycol Dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, ethylene glycol monoacetate, diethylene glycol monoacetate, ethanol, propanol, butanol, diacetone alcohol, Seton, methyl ethyl ketone, methyl isobutyl ketone, N, N-dimethylformamide, 2-methoxyethanol, 2-ethoxyethanol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether , 2-methoxyethyl acetate, 2-ethoxyethyl acetate and the like can be used alone or in combination of two or more.

  In order to dissolve or disperse the toner component in the water-insoluble organic solvent, for example, a device such as a ball mill, a sand mill, a homomixer, or an ultrasonic homogenizer can be used.

  When the resin solution is dispersed in an aqueous medium to form an O / W emulsion, the resin solution and the aqueous system are used by using the same apparatus that can be used for dissolving or dispersing the toner component in the water-insoluble organic solvent. A method of sufficiently stirring the mixed system with the medium can be employed. The O / W type emulsion refers to a suspension in which an oily liquid is dispersed as droplets in an aqueous medium.

  It is preferable to add an appropriate dispersion stabilizer to the aqueous medium. For example, polyvinyl alcohol, gelatin, gum arabic, methyl cellulose, ethyl cellulose, methyl hydroxypropyl cellulose, sodium salt of carboxymethyl cellulose, sodium dodecylbenzene sulfate, sodium dodecylbenzene sulfonate, sodium octyl sulfate, sodium laurate, calcium phosphate, magnesium phosphate, Examples thereof include aluminum phosphate, calcium carbonate, magnesium carbonate, barium sulfate and bentonite. These dispersion stabilizers can be used in an amount of 0.05 to 3% by weight.

  Removal of the water-insoluble organic solvent from the O / W type emulsion can be achieved by heating the O / W type emulsion while stirring, and as a result, a resin fine particle dispersion can be obtained.

  After preparing the first binder resin fine particle dispersion and the second binder resin fine particle dispersion as described above, these dispersion and at least the colorant fine particle dispersion are mixed, and the fine particles are agglomerated / fused. To form core particles. At this time, other toner components such as wax, charge control agent and magnetic powder may be aggregated / fused together with the resin fine particles and colorant fine particles, and the other toner components may be contained in the core particles.

  At the time of agglomeration / fusion, an aggregating agent is added to a mixed dispersion system of at least the first binder resin fine particle dispersion, the second binder resin fine particle dispersion, and the colorant fine particle dispersion to at least the critical aggregation concentration, and each fine particle is salted. Aggregate by precipitation, and further fuse by heating. You may make it fuse | melt simultaneously with making it aggregate. Note that it is not always necessary to perform fusion in this step. This is because the core particles are fused by heating in the shell layer forming step described later.

  Examples of the flocculant include alkali metal salts and alkaline earth metal salts. Examples of the alkali metal include monovalent metals such as lithium, potassium, and sodium. Examples of the alkaline earth metal include divalent metals such as magnesium, calcium, strontium, and barium. A metal is also mentioned. Preferably, potassium, sodium, magnesium, calcium, barium and the like are mentioned. Examples of those constituting salts with these metals include chlorine salts, bromine salts, iodine salts, carbonates, sulfates and the like.

  The colorant fine particle dispersion can be prepared by dispersing a colorant in an aqueous medium. The dispersion of the colorant is performed in a state where the surfactant concentration in water is equal to or higher than the critical micelle concentration (CMC). As the surfactant to be used, anionic surfactants and nonionic surfactants can be used, and these may be used alone or mixed in an appropriate composition. The disperser used for the dispersion treatment of the colorant is not particularly limited, but preferably an ultrasonic disperser, a pressure disperser such as a mechanical homogenizer or a pressure homogenizer, a medium disperser such as a sand grinder or a diamond fine mill. Can be mentioned. Moreover, as a surfactant used, the same thing as the above-mentioned surfactant can be mentioned.

  As the colorant, a known pigment conventionally used as a colorant for full-color toners can be used. For example, carbon black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, dupont oil red, quinoline yellow, methylene blue chloride, copper phthalocyanine, malachite green oxalate, lamp black, rose bengal, CI pigment red 48: 1 CI Pigment Red 122, CI Pigment Red 57: 1, CI Pigment Red 184, CI Pigment Yellow 97, CI Pigment Yellow 12, CI Pigment Yellow 17, CI Solvent Yellow 162, CI Pigment Yellow 180 CI pigment yellow 185, CI pigment blue 15: 1, CI pigment blue 15: 3, and the like.

  The amount of the colorant used is preferably such that the content in the toner particles is 2 to 20 parts by weight, preferably 4 to 15 parts by weight, based on 100 parts by weight of the binder resin. In this specification, “100 parts by weight of the binder resin” is a value based on the total amount of the first binder resin and the second binder resin constituting the core particles and the binder resin for forming a shell layer described later. .

(Shell layer)
In the present invention, since the core particle surface has a shell layer, the core particle and the shell layer can be provided with different functions and separated from each other. As a result, the low-temperature fixability as well as the heat-resistant storage property, mechanical strength, and charging Environmental stability can be effectively secured. Without the shell layer, low-temperature fixability can be secured, but heat-resistant storage stability, mechanical strength, and charging environment stability are reduced.

  The shell layer is made of a binder resin for forming a shell layer, and the type of the resin is not particularly limited. For example, as with the first binder resin and the second binder resin that form the core particles, the core particle is composed of one or more kinds of resins selected from the group consisting of vinyl resins, polyurethane resins, epoxy resins, and polyester resins. It's okay.

  The shell layer may have a single layer structure, or may have a multilayer structure of two or more layers.

  When the shell layer has a single layer structure, the constituent resin of the layer has a Tg of 55 ° C. or more, particularly 55 to 75 ° C., preferably from the viewpoint of further improving the heat resistant storage stability, mechanical strength and charging environment stability of the toner. Is preferably 60 to 70 ° C. Further, from the same viewpoint, Tm is more preferably 100 to 160 ° C, particularly 110 to 140 ° C.

  When the shell layer has a multilayer structure, the physical property values such as Tg of the constituent resin of the outermost layer may be in the above range. In this case, the physical property values such as Tg of the shell layer constituting resin other than the outermost layer are not particularly limited, but are preferably within the above range as in the outermost layer.

The shell layer is prepared by first preparing a dispersion of predetermined binder layer forming binder resin fine particles (hereinafter sometimes referred to as shell particles), and then mixing the obtained dispersion into the core particle dispersion. It can be formed by adhering / fusing shell particles to each other. Specifically, a predetermined amount of shell particle dispersion is added to and mixed with the core particle dispersion, the shell particles are adhered to the surface of the core particles, the core particles are grown, and the shell layer is formed by heating and fusing. In the case of forming a shell layer having a multilayer structure, the shell particles may be mixed and adhered / fused twice or more. In the case of forming a shell layer having a multilayer structure, shell particles constituting a shell layer other than the outermost layer, for example, the first shell layer to be formed first when the shell layer has a two-layer structure are provided. Another toner component may be included in the shell layer by including other toner components such as wax, charge control agent and magnetic powder in the constituting shell particles. In particular, if wax is contained in the shell particles constituting the outermost layer of the shell layer, filming or the like is likely to occur due to liberation of the wax, which is not preferable.
In the present specification, “adhesion / fusion” refers to an action in which adhesion and fusion occur simultaneously or stepwise, or an action that causes adhesion and fusion to occur simultaneously or stepwise.

  The method for preparing the shell particle dispersion is the same as the method for preparing the first and second binder resin fine particle dispersions, except that it is preferable to obtain binder resin fine particles for forming a shell layer having the above physical properties such as Tg. And is appropriately selected according to the type of resin. In particular, the volume average particle diameter of the shell particles is set within the same range as the first and second binder resin fine particles. When the shell particles contain other toner components such as wax, as described above, the other toner components are dispersed in an aqueous medium in advance and seed emulsion polymerization is performed, and the other toner components are polymerized. A method of performing emulsion polymerization by previously dissolving and dispersing in a product, a method of dissolving and dispersing other toner components in a resin solution in advance and forming an O / W type emulsion and removing a water-insoluble organic solvent. Adopt it.

  In order to adhere / fuse the shell particles to the surface of the core particles, this shell layer forming step may be performed continuously to the aggregation / fusion step for obtaining the core particles. That is, a shell particle dispersion is added to a dispersion of core particles obtained by agglomeration / fusion of binder resin fine particles and the like. At this time, in order to grow the core particles by the adhesion of the shell particles, it is preferable to set the reaction temperature at the time of reaching the desired particle size in the aggregation / fusion process or higher.

  In order to promote the adhesion of the shell particles to the core particles, a flocculant used at the time of forming the core particles can be added as appropriate.

  Blending weight ratio of core particle and shell layer, particularly blending weight ratio of all binder resin fine particles (first and second binder resin fine particles) constituting the core particle and all shell particles constituting the shell layer (core: The shell) is preferably 100: 1 to 100: 80, more preferably 100: 3 to 100: 50.

  After the shell particles are attached to the core particles in the shell layer forming process, the cohesive force of the system is completely lost and the particle growth is stopped. Take control. The fusion may be performed by heating to a temperature higher than the glass transition temperature of the shell particles. Further, fusion may be performed simultaneously with the progress of adhesion.

(Toner particles)
Since the toner particles of the present invention having a shell layer formed on the surface of the core particles as described above are dispersed in an aqueous medium, they are usually subjected to post-treatment steps such as a filtration / washing step and a drying step.

  The filtration / washing step performs a filtration process for separating the toner particles from the toner particle dispersion and a washing process for removing a surfactant, an aggregating agent, and the like from the filtered toner particles. Here, examples of the filtration method include, but are not limited to, a centrifugal separation method, a vacuum filtration method using Nutsche and the like, a filtration method using a filter press and the like.

  The drying step is a step of drying the washed toner particles. Examples of dryers used in this process include spray dryers, vacuum freeze dryers, vacuum dryers, etc., stationary shelf dryers, mobile shelf dryers, fluidized bed dryers, rotary dryers A stirring dryer or the like is preferably used. The water content of the dried toner particles is preferably 5% by weight or less, more preferably 2% by weight or less. In addition, when the toner particles that have been dried are aggregated due to weak interparticle attraction, the aggregate may be crushed. Here, as the crushing treatment apparatus, a mechanical crushing apparatus such as a jet mill or a Henschel mixer can be used.

  As described above, the toner particles may contain other toner components such as wax, a charge control agent, and magnetic powder. In particular, when the toner of the present invention is used as a full-color toner used in a full-color image forming apparatus, and a fixing device of a type in which the amount of release oil applied to a fixing member such as a roller is reduced (particularly, When used in an image forming apparatus having an oilless fixing device), wax is preferably contained in the toner particles.

  When the other toner components are contained in the toner particles, their inclusion form is not particularly limited, and may be added in each step as described above. That is, the form of the other toner components contained in the toner particles may be a form contained in the core particles or a form contained in the shell particles.

As the inclusion form in the core particle,
(I) a form in which the core particles are aggregated / fused together with at least the first binder resin fine particles, the second binder resin fine particles, and the colorant fine particles; and (ii) the first binder resin fine particles and / or the second binder particles. Forms contained in the binder resin fine particles;
Is mentioned.

As the inclusion form in the shell particles,
(Iii) When the shell layer has a multilayer structure of two or more layers, the form contained in the binder resin fine particles for forming the shell layer other than the outermost layer;
Is mentioned.

  In particular, the wax is contained in the toner particles in one or more forms selected from the forms (i) to (iii), preferably in the form (i) or (ii), more preferably (i). ) Or a composite form of (ii) and (iii).

  As the wax, waxes known in the field of electrostatic charge image developing toners can be used. For example, polyolefin waxes such as polyethylene wax and polypropylene wax, natural waxes such as carnauba wax and rice wax, montan wax, and Fischer-Tropsch wax. And paraffin wax. When a polyester resin is used as the binder resin, it is preferable to use an oxidized wax from the viewpoint of improving dispersibility.

  The amount of the wax added is preferably such that the content in the toner particles is 0.5 to 12 parts by weight, preferably 1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. When two or more kinds of waxes are used as the wax, and when the wax is contained in two or more containing forms, the total amount thereof may be within the above range.

  As the charge control agent, a known charge control agent that has been conventionally added to control the chargeability in the field of electrostatic image developing toners can be used. For example, fluorine-containing surfactants, metal dyes such as salicylic acid metal complexes, azo metal compounds, polymer acids such as copolymers containing maleic acid as a monomer component, quaternary ammonium salts, nigrosine, etc. An azine dye, carbon black, or the like can be used. The addition amount of the charge control agent is suitably such that the content in the toner particles is 0.01 to 5 parts by weight, preferably 0.05 to 3 parts by weight, based on 100 parts by weight of the binder resin.

(toner)
In the toner of the present invention, an external additive is externally added to the toner particles. As the external additive, known inorganic fine particles used as a fluidity adjusting agent in the field of electrostatic charge image developing toner can be used, for example, silicon carbide, boron carbide, titanium carbide, zirconium carbide, hafnium carbide. , Various carbides such as vanadium carbide, tantalum carbide, niobium carbide, tungsten carbide, chromium carbide, molybdenum carbide, calcium carbide, diamond carbon lactam, various nitrides such as boron nitride, titanium nitride, zirconium nitride, various types such as zirconium boride Various oxides such as boride, titanium oxide (titania), calcium oxide, magnesium oxide, zinc oxide, copper oxide, aluminum oxide, silica, colloidal silica, various titanic acids such as calcium titanate, magnesium titanate, strontium titanate Compound, molybdenum disulfide Sulfides, magnesium fluoride, various fluorides such as carbon fluoride, various metal soaps such as aluminum stearate, calcium stearate, zinc stearate, magnesium stearate, talc, bentonite, etc. They can be used in combination.

  Inorganic fine particles, especially silica, titanium oxide, alumina, zinc oxide, etc. are conventionally used hydrophobizing agents such as silane coupling agents, titanate coupling agents, silicone oils, silicone varnishes, and fluorine-based silanes. It is preferable that the surface treatment is performed by a known method using a coupling agent or a fluorine-based silicone oil, a coupling agent having an amino group or a quaternary ammonium base, or a modified silicone oil.

  The average primary particle size of the inorganic fine particles used as the external additive is 5 to 100 nm, preferably 10 to 50 nm, more preferably 20 to 40 nm.

The present invention does not preclude further external addition of “inorganic fine particles outside the above particle size range” and “organic fine particles” to the toner particles.
Organic fine particles are granulated by emulsion polymerization, soap-free emulsion polymerization, wet polymerization such as non-aqueous dispersion polymerization, gas phase method, etc. for the purpose of cleaning aids, styrene, (meth) acrylic Fine particles such as benzoguanamine, melamine, Teflon (registered trademark), silicon, polyethylene, and polypropylene can be used.

  The toner of the present invention may be used as a full color toner used in a full color image forming apparatus, or may be used as a monochrome toner used in a monochrome image forming apparatus.

The toner of the present invention may be used in an image forming apparatus having any type of fixing device, but the type of fixing device in which the amount of releasing oil applied to a fixing member such as a roller is reduced, That is, it is preferably used in an image forming apparatus having a fixing device in which the amount of release oil applied is 4 mg / m ² or less, particularly a fixing device (oilless fixing device) of a type that does not apply release oil. This is because even when used in such an image forming apparatus, excellent low-temperature fixability can be effectively realized while ensuring good heat-resistant storage stability, mechanical strength and charging environment stability of the toner.
Hereinafter, the present invention will be described in detail with reference to examples.

(Preparation of wax dispersion (1))
680 parts of distilled water, 180 parts of carnauba wax (manufactured by Celarica Noda), 17 parts of sodium dodecylbenzenesulfonate (Neogen SC, manufactured by Daiichi Kogyo Seiyaku) are mixed and emulsified and dispersed by high-pressure shearing to obtain a wax fine particle dispersion. Obtained. When the particle size of the wax fine particles was measured using a dynamic light scattering particle size distribution analyzer, ELS-800 (manufactured by Otsuka Electronics Co., Ltd.), the average particle size was 110 nm.

(Preparation of wax dispersion (2))
680 parts of distilled water, 180 parts of pentaerythritol ester (Unistar H476; manufactured by NOF Corporation) and 17 parts of sodium dodecylbenzenesulfonate (Neogen SC; manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) are mixed, emulsified and dispersed by applying high-pressure shear, and wax. A fine particle dispersion was obtained. When the particle size of the wax fine particles was measured using a dynamic light scattering particle size distribution analyzer, ELS-800 (manufactured by Otsuka Electronics Co., Ltd.), the average particle size was 130 nm.

(Colorant fine particle dispersion (1))
Dissolve 10 parts of sodium dodecylbenzenesulfonate (Neogen SC; manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) in 180 parts of distilled water, add 25 parts of carbon black (Regal 330R; manufactured by Cabot) as fine colorant particles, and disperse. A colorant fine particle dispersion (1) was obtained. When the particle size of the dispersed carbon black was measured using a dynamic light scattering particle size distribution analyzer, ELS-800 (manufactured by Otsuka Electronics Co., Ltd.), the average particle size was 106 nm.

(Colorant fine particle dispersion (2))
Dissolve 10 parts of sodium dodecylbenzenesulfonate (Neogen SC; manufactured by Daiichi Kogyo Seiyaku) in 180 parts of distilled water, and add 25 parts of cyan pigment (copper phthalocyanine B15: 3; manufactured by Dainichi Seika Co., Ltd.) as fine colorant particles. In addition, it was dispersed to obtain a colorant fine particle dispersion (2). When the particle size of the dispersed carbon black was measured using a dynamic light scattering particle size distribution analyzer, ELS-800 (manufactured by Otsuka Kyoko Kogyo Co., Ltd.), the average particle size was 110 nm.

(Preparation of polymer primary fine particle dispersion (1))
A reactor equipped with a stirrer, a condenser, and a temperature sensor was charged with 450 parts of distilled water and 0.56 parts of sodium dodecyl sulfate, heated to 80 ° C. with stirring under a nitrogen stream, and then added with 1 wt% potassium persulfate. 120 parts of an aqueous solution were added. Next, a monomer mixed solution 1 having the following composition was added over 1.5 hours, and then was further maintained for 2 hours to complete the polymerization. After completion of the polymerization reaction, the contents were cooled to room temperature to obtain a milky white polymer primary fine particle dispersion. The weight average molecular weight of the polymer was 11,0O0, Tg was 34 ° C., Tm was 82 ° C., and the average particle size measured with a dynamic light scattering particle size distribution analyzer (ELS-800; manufactured by Otsuka Electronics Co., Ltd.) was 120 nm. It was.
<Monomer mixture 1>
Styrene 99 parts Butyl acrylate 52 parts Methacrylic acid 14 parts
n-octyl mercaptan 6 parts

(Preparation of polymer primary fine particle dispersion (2))
A reactor equipped with a stirrer, a condenser, and a temperature sensor was charged with 450 parts of distilled water and 0.56 parts of sodium dodecyl sulfate, heated to 80 ° C. with stirring under a nitrogen stream, and then added with 1 wt% potassium persulfate. 120 parts of an aqueous solution were added. Next, after adding monomer mixed solution 2 having the following composition over 1.5 hours, the mixture was further maintained for 2 hours to complete the polymerization. After completion of the polymerization reaction, the contents were cooled to room temperature to obtain a milky white primary polymer fine particle dispersion. The weight average molecular weight of the polymer was 62,000, Tg was 65 ° C., Tm was 130 ° C., and the average particle size measured by a dynamic light scattering particle size distribution analyzer (ELS-800; manufactured by Otsuka Electronics Co., Ltd.) was 120 nm.
<Monomer mixture 2>
Styrene 125 parts Butyl acrylate 40 parts Methacrylic acid 2.5 parts
n-octyl mercaptan 3 parts

(Preparation of polymer primary fine particle dispersion (3))
A reactor equipped with a stirrer, condenser, and temperature sensor was charged with 45 parts of wax dispersion (2), 450 parts of distilled water and 0.56 parts of sodium dodecyl sulfate, and the temperature was raised to 80 ° C. while stirring under a nitrogen stream. Thereafter, 120 parts of a 1 wt% aqueous potassium persulfate solution was added thereto. Next, after adding monomer mixed solution 3 having the following composition over 1.5 hours, the mixture was further maintained for 2 hours to complete the polymerization. After completion of the polymerization reaction, the contents were cooled to room temperature to obtain a milky white primary polymer fine particle dispersion. The weight average molecular weight of the polymer was 48,000, Tg was 55 ° C., Tm was 110 ° C., and the average particle size measured by a dynamic light scattering particle size distribution analyzer (ELS-800; manufactured by Otsuka Electronics Co., Ltd.) was 130 nm.
<Monomer mixture 3>
Styrene 120 parts Butyl acrylate 38 parts Methacrylic acid 13 parts
n-octyl mercaptan 3 parts

(Preparation of polymer primary fine particle dispersion (4))
In a 10-liter four-necked flask equipped with a stirrer, distillation column, inert gas introduction tube, thermometer, 2200 parts by weight of polyoxyethylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, 120 parts by weight of neopentyl glycol, 1100 parts by weight of terephthalic acid, and 200 parts by weight of isophthalic acid were charged, and the temperature was raised to 180 ° C. in a nitrogen gas stream, where 5 parts by weight of dibutyltin oxide was added and heated for 2 hours. Next, the temperature was raised to 230 ° C., and water was no longer distilled from the distillation tower, and the reaction was carried out until the acid value reached 4.2 KOH mg / g and the softening point reached 85 ° C. to obtain polyester resin A. Polyester resin A had a glass transition point of 36 ° C., a number average molecular weight of 4,20O, and a weight average molecular weight / number average molecular weight of 3.5.

Next, 20 parts of polyester resin A, 70 parts of ethyl acetate and 30 parts of MEK are placed in a beaker and stirred at 12000 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) to uniformly dissolve and disperse the polyester resin solution. Was prepared.
On the other hand, a thermometer and a stirrer were attached to a three-necked flask, and an aqueous medium was prepared by dissolving 0.5% by weight of a dispersant (sodium dodecylbenzenesulfonate) and 0.5% by weight of polyvinyl alcohol in 450 parts of ion-exchanged water.
The resin solution was suspended in the aqueous medium using a TK homomixer to form an O / W type emulsion. At this time, the TK homomixer was stirred at 10000 rpm for 30 minutes. Thereafter, the mixed solvent was removed by heating with stirring at 200 rpm in a TK homomixer to obtain a polymer primary fine particle dispersion (4) having a volume average particle size of 150 nm.

(Preparation of polymer primary fine particle dispersion (5))
A reactor equipped with a stirrer, a condenser, and a temperature sensor was charged with 450 parts of distilled water and 0.56 part of sodium dodecyl sulfate, heated to 80 ° C. with stirring under a nitrogen stream, and then 1 wt% potassium persulfate. 120 parts of an aqueous solution were added. Next, after adding the monomer mixed solution 4 having the following composition over 1.5 hours, the mixture was further maintained for 2 hours to complete the polymerization. After completion of the polymerization reaction, the contents were cooled to room temperature to obtain a milky white primary polymer fine particle dispersion. The weight average molecular weight of the polymer was 9,800, Tg was 30 ° C., Tm was 78 ° C., and the average particle size measured by a dynamic light scattering particle size distribution analyzer (ELS-800; manufactured by Otsuka Electronics Co., Ltd.) was 110 nm.
<Monomer mixture 4>
Styrene 95 parts Butyl acrylate 58 parts Methacrylic acid 12 parts n-Octyl mercaptan 8 parts

(Example 1)
In a reactor equipped with a stirrer, cooling tube and temperature sensor, 140 parts of polymer primary particle dispersion (1), 100 parts of polymer primary fine particle dispersion (2), 13.6 parts of wax dispersion wave (1), colorant Charge 24 parts of fine particle dispersion (1), 5 parts of an anionic surfactant (Neogen SC; manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and 240 parts of distilled water, and add 2N sodium hydroxide aqueous solution while stirring. The pH of the dispersion was adjusted to 10.0. Next, 40 parts of a 50 wt% magnesium chloride aqueous solution was added thereto, and then the temperature was raised to 80 ° C. with stirring and held for 0.5 hours, and then heated to 88 ° C. and held for another 0.5 hours. At this time, the average particle size of the toner in the mixed dispersion was 4.2 μm. Next, after cooling the temperature in the system to 75 ° C., 20 parts of the polymer primary fine particle dispersion (3) was added, the temperature was raised to 83 ° C. and held for 1.5 hours, and then the polymer primary fine particle dispersion ( 2) 30 parts were added, heated to 85 ° C. and held for 1.5 hours, then 120 g of 20 wt% sodium chloride aqueous solution was added, then heated to 92 ° C. and held for 1 hour. Thereafter, the contents are cooled to room temperature, and the toner particles having a volume average particle diameter of 4.6 μm are dried by repeating the washing process such as filtration of the solution and resuspension treatment of the obtained solid in distilled water several times, followed by drying. Got one. With respect to 100 parts by weight of the toner particles, 0.5 part by weight of hydrophobic silica (H-2000; manufactured by Clariant), 1.0 part by weight of titanium oxide (STT30A: manufactured by Titanium Industry Co., Ltd.), strontium titanate (average particle size 0.2 μm) ) 1.0 part by weight was added, mixed with a Henschel mixer (circumferential speed 40 m / sec, 60 seconds), and then sieved with a sieve having an opening of 90 μm to obtain a toner.

(Example 2)
In Example 1, instead of using the colorant fine particle dispersion (1), toner particles 2 having a volume average particle diameter of 4.6 μm were obtained by the same operation using the colorant fine particle dispersion (2). With respect to 100 parts by weight of the toner particles, 0.5 part by weight of hydrophobic silica (H-2000; manufactured by Clariant), 1.0 part by weight of titanium oxide (STT30A: manufactured by Titanium Industry Co., Ltd.), strontium titanate (average particle size 0.2 μm) ) 1.0 part by weight was added, mixed with a Henschel mixer (circumferential speed 40 m / sec, 60 seconds), and then sieved with a sieve having an opening of 90 μm to obtain a toner.

(Example 3)
In Example 1, instead of using the wax dispersion liquid (1), toner particles 3 having a volume average particle diameter of 4.4 μm were obtained by the same operation using the wax dispersion liquid (2). To 100 parts by weight of the toner particles, 0.5 part by weight of hydrophobic silica (H-2000; manufactured by Clariant), 1.0 part by weight of titanium oxide (STT30A: manufactured by Titanium Industry Co., Ltd.), strontium titanate (average particle size 0.2 μm) ) 1.0 part by weight was added, mixed with a Henschel mixer (circumferential speed 40 m / sec, 60 seconds), and then sieved with a sieve having an opening of 90 μm to obtain a toner.

(Example 4)
In a reactor equipped with a stirrer, a condenser, and a temperature sensor, 140 parts of polymer primary particle dispersion (1), 100 parts of polymer primary particle dispersion (3), 24 parts of colorant particle dispersion (1), Then, 240 parts of distilled water was added, and 2N aqueous sodium hydroxide solution was added with stirring to adjust the pH of the mixed dispersion to 10.0. Next, 40 parts of a 50 wt% magnesium chloride aqueous solution was added thereto, and then the temperature was raised to 85 ° C. with stirring and held for 1.5 hours. The average particle size of the mixed dispersion at this time was 4.1 μm. Next, after cooling the temperature in the system to 75 ° C., 20 parts of the polymer primary fine particle dispersion (3) was added, the temperature was raised to 83 ° C. and held for 1.5 hours, and then the polymer primary fine particle dispersion ( 2) 30 parts were added, heated to 85 ° C. and held for 1.5 hours, then 120 g of 20 wt% sodium chloride aqueous solution was added, then heated to 92 ° C. and held for 1 hour. Thereafter, the contents are cooled to room temperature, and the washing process such as filtration of the solution and resuspension treatment of the obtained solid content in distilled water is repeated several times, and the toner particles 4 having a volume average particle diameter of 4.3 μm are dried. Got. With respect to 100 parts by weight of the toner particles, 0.5 part by weight of hydrophobic silica (H-2000; manufactured by Clariant), 1.0 part by weight of titanium oxide (STT30A: manufactured by Titanium Industry Co., Ltd.), strontium titanate (average particle size 0.2 μm) ) 1.0 part by weight was added, mixed with a Henschel mixer (circumferential speed 40 m / sec, 60 seconds), and then sieved with a sieve having an opening of 90 μm to obtain a toner.

(Example 5)
In Example 1, instead of using the polymer primary fine particle dispersion (1), toner particles 5 having a volume average particle diameter of 4.6 μm were obtained by the same operation using the polymer primary fine particle dispersion (4). With respect to 100 parts by weight of the toner particles, 0.5 part by weight of hydrophobic silica (H-2000; manufactured by Clariant), 1.0 part by weight of titanium oxide (STT30A: manufactured by Titanium Industry Co., Ltd.), strontium titanate (average particle size 0.2 μm) ) 1.0 part by weight was added, mixed with a Henschel mixer (circumferential speed 40 m / sec, 60 seconds), and then sieved with a sieve having an opening of 90 μm to obtain a toner.

(Example 6)
In a reactor equipped with a stirrer, a condenser, and a temperature sensor, 70 parts of polymer primary particle dispersion (1), 100 parts of polymer primary fine particle dispersion (2), 70 parts of polymer primary fine particle dispersion (4) , 13.6 parts of the wax dispersion (1), 24 parts of the colorant fine particle dispersion wave (1), 5 parts of an anionic surfactant (Neogen SC; manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and 240 parts of distilled water are stirred and stirred. While adding 2N aqueous sodium hydroxide solution, the pH of the mixed dispersion was adjusted to 10.0. Next, 40 parts of a 50 wt% magnesium chloride aqueous solution was added thereto, and then the temperature was raised to 80 ° C. with stirring and held for 0.5 hours, and then heated to 88 ° C. and held for another 0.5 hours. At this time, the average particle size of the toner in the mixed dispersion was 4.2 μm. Next, after cooling the temperature in the system to 75 ° C., 48 parts of the polymer primary fine particle dispersion (3) was added, and the temperature was raised to 83 ° C. and held for 1.5 hours, and then the polymer primary fine particle dispersion ( 2) 60 parts were added, heated to 85 ° C. and held for 1.5 hours, then 120 g of 20 wt% sodium chloride aqueous solution was added, then heated to 92 ° C. and held for 1 hour. Thereafter, the contents are cooled to room temperature, and the washing process such as filtration of the solution and resuspension treatment of the obtained solid content in distilled water is repeated several times and dried to dry the toner particles 6 having a volume average particle diameter of 4.5 μm. Got. With respect to 100 parts by weight of the toner particles, 0.5 part by weight of hydrophobic silica (H-2000; manufactured by Clariant), 1.0 part by weight of titanium oxide (STT30A: manufactured by Titanium Industry Co., Ltd.), strontium titanate (average particle size 0.2 μm) ) 1.0 part by weight was added, mixed with a Henschel mixer (circumferential speed 40 m / sec, 60 seconds), and then sieved with a sieve having an opening of 90 μm to obtain a toner.

(Example 7)
In a reactor equipped with a stirrer, a condenser, and a temperature sensor, 140 parts of polymer primary fine particle dispersion (1), 100 parts of polymer primary fine particle dispersion (2), 13.6 parts of wax dispersion (1), colorant Charge 24 parts of fine particle dispersion (1), 5 parts of an anionic surfactant (Neogen SC; manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and 240 parts of distilled water, and add 2N sodium hydroxide aqueous solution while stirring. The pH of the dispersion was adjusted to 10.0. Next, 40 parts of a 50 wt% magnesium chloride aqueous solution was added thereto, and then the temperature was raised to 80 ° C. with stirring and held for 0.5 hours, and then heated to 88 ° C. and held for another 0.5 hours. At this time, the average particle size of the toner in the mixed dispersion was 4.3 μm. Next, after cooling the temperature in the system to 75 ° C., 50 parts of the polymer primary fine particle dispersion (2) was added, the temperature was raised to 85 ° C. and held for 1.5 hours, and then 120 g of a 20 wt% sodium chloride aqueous solution was added. After the addition, the temperature was raised to 92 ° C. and held for 1 hour. Thereafter, the contents are cooled to room temperature, and the toner particles 7 having a volume average particle size of 4.7 μm are dried by repeating several times of washing treatment such as filtration of the solution and resuspension treatment of the obtained solid in distilled water. Got. With respect to 100 parts by weight of the toner particles, 0.5 part by weight of hydrophobic silica (H-2000; manufactured by Clariant), 1.0 part by weight of titanium oxide (STT30A; manufactured by Titanium Industry Co., Ltd.), strontium titanate (average particle size 0.2 μm) ) 1.0 part by weight was added, mixed with a Henschel mixer (circumferential speed 40 m / sec, 60 seconds), and then sieved with a sieve having an opening of 90 μm to obtain a toner.

(Comparative Example 1)
In a reactor equipped with a stirrer, condenser, temperature sensor, polymer primary particle dispersion (2) 288 parts, wax dispersion (1) 13.6 parts, colorant fine particle dispersion (1) 24 parts, and distilled water 240 parts were added, and 2N aqueous sodium hydroxide solution was added with stirring to adjust the pH of the mixed dispersion to 10.0. Next, 40 parts of a 50 wt% magnesium chloride aqueous solution was added thereto, and then the temperature was raised to 70 ° C. with stirring and held for 1.5 hours. The average particle size of the mixed dispersion at this time was 4.5 μm. Next, 120 parts of a 20 wt% sodium chloride aqueous solution was added, and then the temperature was raised to 92 ° C. and held for 1 hour. Thereafter, the contents are cooled to room temperature, and the toner particles 8 having a volume average particle size of 4.4 μm are dried by repeating the washing process such as filtration of the solution and resuspension treatment of the obtained solid in distilled water several times. Got. With respect to 100 parts by weight of the toner particles, 0.5 part by weight of hydrophobic silica (H-2000; manufactured by Clariant), 1.0 part by weight of titanium oxide (STT30A: manufactured by Titanium Industry Co., Ltd.), strontium titanate (average particle size 0.2 μm) ) 1.0 part by weight was added, mixed with a Henschel mixer (circumferential speed 40 m / sec, 60 seconds), and then sieved with a sieve having an opening of 90 μm to obtain a toner.

(Comparative Example 2)
In a reactor equipped with a stirrer, condenser, and temperature sensor, 240 parts of polymer primary particle dispersion (2), 13.6 parts of wax dispersion (1), 24 parts of fine colorant dispersion (2), and distilled water 240 parts were added, and 2N aqueous sodium hydroxide solution was added with stirring to adjust the pH of the mixed dispersion to 10.0. Next, 40 parts of a 50 wt% magnesium chloride aqueous solution was added thereto, and then the temperature was raised to 85 ° C. with stirring and held for 1.5 hours. The average particle size of the mixed dispersion at this time was 4.2 μm. Next, after cooling the temperature in the system to 75 ° C., 50 parts of the polymer primary fine particle dispersion (2) was added, the temperature was raised to 83 ° C. and held for 0.5 hours, and then 120 parts of a 20 wt% sodium chloride aqueous solution. Was added, and the temperature was raised to 92 ° C. and held for 1 hour. Thereafter, the contents are cooled to room temperature, and washing treatment such as filtration of the solution and resuspension treatment of the obtained solid content in distilled water is repeated several times and dried to dry the toner particles 9 having a volume average particle diameter of 4.3 μm. Got. With respect to 100 parts by weight of the toner particles, 0.5 part by weight of hydrophobic silica (H-2000; manufactured by Clariant), 1.0 part by weight of titanium oxide (STT30A: manufactured by Titanium Industry Co., Ltd.), strontium titanate (average particle size 0.2 μm) ) 1.0 part by weight was added, mixed with a Henschel mixer (circumferential speed 40 m / sec, 60 seconds), and then sieved with a sieve having an opening of 90 μm to obtain a toner.

(Comparative Example 3)
In a reactor equipped with a stirrer, cooling tube and temperature sensor, 240 parts of polymer primary fine particle dispersion (1), 13.6 parts of wax dispersion (1), 24 parts of colorant fine particle dispersion (1), anionic interface 5 parts of an activator (Neogen SC; manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and 240 parts of distilled water were charged, and a 2N aqueous sodium hydroxide solution was added with stirring to adjust the pH of the mixed dispersion to 10.0. Next, 40 parts of a 50 wt% magnesium chloride aqueous solution was added thereto, and then the temperature was raised to 80 ° C. with stirring and held for 1.5 hours. The average particle diameter of the mixed dispersion at this time was 4.6 μm. Next, after cooling the temperature in the system to 75 ° C., 50 parts of the polymer primary fine particle dispersion (2) was added, the temperature was raised to 83 ° C. and held for 0.5 hours, and then 120 parts of a 20 wt% sodium chloride aqueous solution. Was added, and the temperature was raised to 92 ° C. and held for 1 hour. Thereafter, the contents are cooled to room temperature, and the toner particles 10 having a volume average particle diameter of 4.7 μm are dried by repeating the washing process such as filtration of the solution and resuspension treatment of the obtained solid in distilled water several times and drying. Got. With respect to 100 parts by weight of the toner particles, 0.5 part by weight of hydrophobic silica (H-2000; manufactured by Clariant), 1.0 part by weight of titanium oxide (STT30A; manufactured by Titanium Industry Co., Ltd.), strontium titanate (average particle size 0.2 μm) ) 1.0 part by weight was added, mixed with a Henschel mixer (circumferential speed 40 m / sec, 60 seconds), and then sieved with a sieve having an opening of 90 μm to obtain a toner.

(Comparative Example 4)
In a reactor equipped with a stirrer, cooling tube, temperature sensor, 140 parts of polymer primary fine particle dispersion (1), 100 parts of polymer primary fine particle dispersion (5), 13.6 parts of wax dispersion (1), colorant Charge 24 parts of fine particle dispersion (1), 5 parts of an anionic surfactant (Neogen SC; manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and 240 parts of distilled water, and add 2N sodium hydroxide aqueous solution while stirring. The pH of the dispersion was adjusted to 10.0. Next, 40 parts of a 50 wt% magnesium chloride aqueous solution was added thereto, and then the temperature was raised to 80 ° C. with stirring and held for 0.5 hours, and then heated to 88 ° C. and held for another 0.5 hours. At this time, the average particle size of the toner in the mixed dispersion was 4.2 μm. Next, after cooling the temperature in the system to 75 ° C., 50 parts of the polymer primary fine particle dispersion (2) was added, the temperature was raised to 85 ° C. and held for 1.5 hours, and then 120 g of 20 wt% sodium chloride aqueous solution was added. After the addition, the temperature was raised to 92 ° C. and held for 1 hour. Thereafter, the content is cooled to room temperature, and the toner particles 11 having a volume average particle diameter of 4.5 μm are dried by repeating the washing process such as filtration of the solution and resuspension treatment of the obtained solid in distilled water several times and drying. Got. With respect to 100 parts by weight of the toner particles, 0.5 part by weight of hydrophobic silica (H-2000; manufactured by Clariant), 1.0 part by weight of titanium oxide (STT30A; manufactured by Titanium Industry Co., Ltd.), strontium titanate (average particle size 0.2 μm) ) 1.0 part by weight was added, mixed with a Henschel mixer (circumferential speed 40 m / sec, 60 seconds), and then sieved with a sieve having an opening of 90 μm to obtain a toner.

(Comparative Example 5)
In a reactor equipped with a stirrer, cooling tube, temperature sensor, 140 parts of polymer primary fine particle dispersion (2), 100 parts of polymer primary fine particle dispersion (3), 13.6 parts of wax dispersion (1), colorant Charge 24 parts of fine particle dispersion (1), 5 parts of an anionic surfactant (Neogen SC; manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and 240 parts of distilled water, and add 2N sodium hydroxide aqueous solution while stirring. The pH of the dispersion was adjusted to 10.0. Next, 40 parts of a 50 wt% magnesium chloride aqueous solution was added thereto, and then the temperature was raised to 80 ° C. with stirring and held for 0.5 hours, and then heated to 88 ° C. and held for another 0.5 hours. At this time, the average particle size of the toner in the mixed dispersion was 4.3 μm. Next, after cooling the temperature in the system to 75 ° C., 50 parts of the polymer primary fine particle dispersion (2) was added, the temperature was raised to 85 ° C. and held for 1.5 hours, and then 120 g of a 20 wt% sodium chloride aqueous solution was added. After the addition, the temperature was raised to 92 ° C. and held for 1 hour. Thereafter, the contents are cooled to room temperature, and the toner particles 12 having a volume average particle diameter of 4.6 μm are dried by repeating the washing process such as filtration of the solution and resuspension treatment of the obtained solid content in distilled water several times. Got. With respect to 100 parts by weight of the toner particles, 0.5 part by weight of hydrophobic silica (H-2000; manufactured by Clariant), 1.0 part by weight of titanium oxide (STT30A; manufactured by Titanium Industry Co., Ltd.), strontium titanate (average particle size 0.2 μm) ) 1.0 part by weight was added, mixed with a Henschel mixer (circumferential speed 40 m / sec, 60 seconds), and then sieved with a sieve having an opening of 90 μm to obtain a toner.

(Comparative Example 6)
In a reactor equipped with a stirrer, cooling tube, temperature sensor, 140 parts of polymer primary fine particle dispersion (1), 100 parts of polymer primary fine particle dispersion (5), 13.6 parts of wax dispersion (1), colorant Charge 24 parts of fine particle dispersion (1), 5 parts of an anionic surfactant (Neogen SC; manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and 240 parts of distilled water, and add 2N sodium hydroxide aqueous solution while stirring. The pH of the dispersion was adjusted to 10.0. Next, 40 parts of a 50 wt% magnesium chloride aqueous solution was added thereto, and then the temperature was raised to 80 ° C. with stirring and held for 0.5 hours, and then heated to 88 ° C. and held for another 0.5 hours. The average particle size of the toner in the mixed dispersion at this time was 4.5 μm. Next, after adding 120 g of a 20 wt% sodium chloride aqueous solution, the temperature was raised to 92 ° C. and held for 1 hour. Thereafter, the contents are cooled to room temperature, and the toner particles 13 having a volume average particle diameter of 4.4 μm are dried by repeating the washing process such as filtration of the solution and resuspension treatment of the obtained solid in distilled water several times. Got. With respect to 100 parts by weight of the toner particles, 0.5 part by weight of hydrophobic silica (H-2000; manufactured by Clariant), 1.0 part by weight of titanium oxide (STT30A; manufactured by Titanium Industry Co., Ltd.), strontium titanate (average particle size 0.2 μm) ) 1.0 part by weight was added, mixed with a Henschel mixer (circumferential speed 40 m / sec, 60 seconds), and then sieved with a sieve having an opening of 90 μm to obtain a toner.

(Comparative Example 7)
In a reactor equipped with a stirrer, a condenser, and a temperature sensor, 140 parts of polymer primary fine particle dispersion (1), 100 parts of polymer primary fine particle dispersion (2), 13.6 parts of wax dispersion (1), colorant Charge 24 parts of fine particle dispersion (1), 5 parts of an anionic surfactant (Neogen SC; manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and 240 parts of distilled water, and add 2N sodium hydroxide aqueous solution while stirring. The pH of the dispersion was adjusted to 10.0. Next, 40 parts of a 50 wt% magnesium chloride aqueous solution was added thereto, and then the temperature was raised to 80 ° C. with stirring and held for 0.5 hours, and then heated to 88 ° C. and held for another 0.5 hours. At this time, the average particle size of the toner in the mixed dispersion was 4.4 μm. Next, after adding 120 g of a 20 wt% sodium chloride aqueous solution, the temperature was raised to 92 ° C. and held for 1 hour. Thereafter, the content is cooled to room temperature, and washing treatment such as filtration of the solution and resuspension treatment of the obtained solid in distilled water is repeated several times and dried to dry the toner particles 14 having a volume average particle diameter of 4.3 μm. Got. With respect to 100 parts by weight of the toner particles, 0.5 part by weight of hydrophobic silica (H-2000; manufactured by Clariant), 1.0 part by weight of titanium oxide (STT30A; manufactured by Titanium Industry Co., Ltd.), strontium titanate (average particle size 0.2 μm) ) 1.0 part by weight was added, mixed with a Henschel mixer (circumferential speed 40 m / sec, 60 seconds), and then sieved with a sieve having an opening of 90 μm to obtain a toner.

(Manufacture of binder type carrier)
In order to use the toners obtained in the above Examples and Comparative Examples as a two-component developer for evaluation, a binder type carrier was manufactured. Henschel mixer 100 parts by weight of polyester resin (Kao Corporation: NE-1110), 700 parts by weight of magnetic particles (magnetite; EPT-1000: Toda Kogyo Co., Ltd.) and 2 parts by weight of carbon black (Mogal L; manufactured by Cabot Corporation) Then, the mixture was melted and kneaded by setting the cylinder part at 180 ° C. and the cylinder head part at 170 ° C. with a twin screw extrusion kneader. The kneaded product was cooled, then coarsely pulverized with a hammer mill, finely pulverized with a jet pulverizer, and classified to obtain a binder-type carrier having a volume average particle size of 40 μm.

(Toner characteristics evaluation method)
-Heat-resistant storage property After 10g of toner was left at a high temperature of 50 ° C for 24 hours, the toner was visually observed and evaluated.
○: No aggregate was observed;
Δ: Less than 10 aggregates were present;
X: There were 10 or more aggregates.

In the following evaluation, a developer obtained by mixing toner and carrier so that the toner concentration was 6% by weight was used.
-Fixability Fixability was evaluated comprehensively from the evaluation results of peel resistance and offset resistance.
○: The results of all items were “◎” or “○”;
Δ: “△” was included in addition to “◎” or “○”;
×: At least one “×” was included.

<Peeling resistance>
With a digital copying machine (DIALTA Di350; manufactured by Minolta Co., Ltd.) equipped with an oil-less fixing unit while changing the fixing temperature in the range of 80 to 130 ° C in 2 ° C increments, the solid image (attachment amount) 2.0 mg / cm ² ), each image was folded in half from the middle, and the peel resistance of the image was visually evaluated. The temperature between the fixing temperature when the image was slightly peeled off and the lower fixing temperature at which the image was not peeled at all was defined as the fixing lower limit temperature.
A: The minimum fixing temperature was less than 102 ° C .;
○: The minimum fixing temperature was 102 ° C. or higher and lower than 106 ° C .;
Δ: Fixing lower limit temperature was 106 ° C. or higher and lower than 112 ° C .;
X: The minimum fixing temperature was 112 ° C. or higher.

<Offset resistance>
Set the fixing system speed of the digital copying machine (DIALTA Di350; manufactured by Minolta Co., Ltd.) to 1/2 and take a halftone image while changing the fixing temperature in increments of 5 ° C in the range of 90 ° C to 150 ° C. The lower limit temperature at which the high temperature offset occurs was evaluated as an offset temperature.
A: Offset temperature was 128 ° C. or higher;
○: The offset temperature was 120 ° C or higher and lower than 128 ° C;
Δ: Offset temperature was 115 ° C. or higher and lower than 120 ° C .;
X: The offset temperature was less than 115 ° C.

-Charging environment stability (environmental stability)
The charging environment is stable due to the difference between the charge amount of the developer stored for 24 hours in a low-temperature, low-humidity environment (10 ° C, 15%) and the charge amount of the developer stored for 24 hours in a high-temperature, high-humidity environment (30 ° C, 85%). Sex was evaluated.
A: The absolute value of the difference was less than 4 μC / g;
○: The absolute value of the difference was 4 μC / g or more and less than 6 μC / g;
Δ: The absolute value of the difference was 6 μC / g or more and less than 8 μC / g;
X: The absolute value of the difference was 8 μC / g or more and less than 10 μC / g;
XX: The absolute value of the difference was 10 μC / g or more.

-Stress resistance The stress resistance was evaluated by the presence or absence of a phenomenon in which toner particles that were crushed or worn out adhered to the surface of the photoconductor in a thin layer due to continuous use of the toner.
○: Adherence of toner particles was not visually recognized;
X: Adherence of toner particles was visually recognized.

(Method for measuring properties of toner and resin particles)
When the resin fine particles (polymer primary fine particles) contain other toner components such as wax, the physical property value of the resin is the same as the method for forming other toner component-containing resin fine particles, except that the other toner components are not contained. It is the measured value of the resin fine particles formed by the method.
-Volume average particle diameter of toner Volume average particle diameter (D) was measured using Coulter Multisizer II (manufactured by Coulter Counter) using an aperture tube of 50 µm.
・ Circularity Circularity is expressed as “perimeter of equivalent circle / perimeter of particle projection image”. The average circularity was measured in a water dispersion system using a flow type particle image analyzer (FPIA-2000: manufactured by Sysmex Corporation).

・ Glass transition temperature Tg
Using a differential scanning calorimeter (DSC-200: manufactured by Seiko Electronics Co., Ltd.), accurately weigh 10 mg of the sample to be measured, place it in an aluminum pan, and heat up using a sample in which alumina is placed in an aluminum pan as a reference. After raising the temperature from room temperature to 200 ° C at a rate of 30 ° C / min, this is cooled and measured between 20-120 ° C at a rate of temperature increase of 10 ° C / min. The shoulder value of the main endothermic peak in this range was taken as the glass transition point.

・ Softening point Tm
Using a flow tester (CFT-500: manufactured by Shimadzu Corporation), weigh 1.0 g of the sample to be measured, use a die with a diameter of 1.Omm x length of 1.0 mm, a heating rate of 3.0 ° C / min, and a preheating time of 180 Measurement was performed under conditions of a second, a load of 30 kg, and a measurement temperature range of 60 to 180 ° C., and the temperature at which the sample flowed out 1/2 was defined as a softening point.

-Molecular weight It measured using the gel permeation chromatography (807-IT type: JASCO Corporation make). While maintaining the column temperature at 40 ° C., tetrahydrofuran as a carrier solvent was flowed at 1 kg / cm ² , 30 mg of a sample to be measured was dissolved in 20 ml of tetrahydrofuran, 0.5 mg of this solution was introduced into the apparatus together with the above carrier solvent, and polystyrene Calculated by conversion.

Claims (5)

  It contains toner particles having at least a first binder resin having a softening point of less than 100 ° C., a second binder resin having a softening point of 100 ° C. or more, and a core particle surface made of a colorant and having a shell layer. Toner for developing electrostatic images.   The core particles are formed by agglomerating / fusing at least the first binder resin fine particles, the second binder resin fine particles, and the colorant fine particles, and the shell layer adheres / fuses the binder resin fine particles for forming the shell layer to the core particle surface The toner for developing an electrostatic charge image according to claim 1, wherein the treatment is performed once or twice or more.   The first binder resin, the second binder resin, and the shell layer forming binder resin are each independently selected from one or more types of resins selected from the group consisting of vinyl resins, polyurethane resins, epoxy resins, and polyester resins. The electrostatic image developing toner according to claim 1, wherein the toner is for electrostatic image development. 4. The electrostatic image developing toner according to claim 1, wherein the toner particles contain wax in one or more forms selected from the following forms (i) to (iii): ;
(I) A form in which the wax is aggregated / fused together with at least the first binder resin fine particles, the second binder resin fine particles, and the colorant fine particles when forming the core particles;
(Ii) a form in which the wax is contained in the first binder resin fine particles and / or the second binder resin fine particles; and (iii) when the shell layer has a multilayer structure of two or more layers, the wax is a shell other than the outermost layer. The form contained in the binder resin fine particles for layer formation. When the shell layer has a single-layer structure, the constituent resin of the layer has a glass transition temperature of 55 ° C. or more when the shell layer has a multilayer structure of two or more layers. The toner for developing an electrostatic charge image according to claim 1.